There is a common misconception that vacuum regulators protect against leaks of
pressurized hazardous gases. It is reasoned the vacuum created in the feed line
will draw outside air through any puncture or break in the line rather than allowing
the chemical to flow out into the surrounding area. This misconception poses a potentially
serious safety hazard.

Figure 1 highlights the lead gasket that seals the junction between the yoke on
the vacuum regulator and the valve on the ton container. Even with a vacuum regulator
installed and functioning properly, this junction is at the pressure of the ton
container. There is no vacuum here. The lead gasket alone seals the internal pressure
of the ton container and prevents the chemical from leaking out. If the vacuum regulator
is bumped, or if the yoke loosens for any reason, the pressurized chemical will
leak past this gasket.

Without a Powell emergency shutdown system in place, any leak at the lead gasket
could continue until a responder puts on a HAZMAT suit and enters the room to physically
shut off the container valve. By that time, the leak could be reportable and hazardous.

No vacuum regulator can stop this kind of leak, but a Powell Emergency Valve Closure
System can in less than 5 seconds.

With or Without a Vacuum Regulator, Powell Valve Closure Systems Offer Complete
Protection against Hazardous Leaks

Piping Modifications Can Be Safely Made to Accommodate Most Vacuum Regulators

Some vacuum regulators used on ton containers can block direct access to the valve
stem. In this situation, the vacuum regulator body can be moved out of the way by
adding the appropriate couplings, nipples, or elbows. Occasionally, an additional
yoke may be required, depending on the make and model of the vacuum regulator in
use. As long as forged steel 3000 lb fittings and appropriate sealants are used,
these piping modifications will not add additional risk of a chemical leak because
the MaxPro™ RA or E-Pro®
will be mounted on the container valve. Even if the vacuum regulator must be mounted
on a remote manifold in order to clear the valve closure actuator, the entire process
will still be protected because the MaxPro™ RA and the E-Pro® will close
the container valve at the very origin of the chemical flow.